TL;DR Summary

Carbs are used to fill your glycogen stores within your liver and muscles before ever getting close to your fat cells.

Insulin is anabolic. Get on the anabolic train.

Muscle contraction activates GLUT4, which increases liver and muscle glucose uptake and increases insulin sensitivity, allowing more carbs to be eaten around workouts.

Carbs are not evil, but awesome. Eat them!

Find a list at the bottom to find out how to minimise fat gain while eating carbs.

“Will carbs make me fat?”

I always get asked this from people who are starting to focus on their eating, instead of just hoping that if they exercise enough they can eat however much they want.
The transition from the belief that “carbs are evil and will make me fat” to “carbs are awesome and damn, I look good”, can take some time.

The main thing to understand is that carbs ARE the bodies preferred source of energy. Whatever carbs you do eat, majority of them end up in your blood stream as glucose and are then stored as glycogen in your muscle and liver cells before they ever get close to your fat cells.

Be it sugary snacks to whole grains to veggies and fruits. Glucose and stored glycogen is used in the glycolytic and oxidative energy systems to regenerate ATP stores for energy and cellular work. Your brain also runs on glucose, it loves the stuff and your body will fight for its right to have a stable amount of glucose (sugar) running through your blood stream, to operate optimally. You can’t beat science on this. If you want optimum performance, mentally and physically, you better be eating some carbs!

Now, it can also be converted through chemical reactions to fatty acids and be stored as triglycerides in your fat cells (body fat). I’ll explain how a bit later. Don’t be scared though, if you read this article, you will come out of it understanding how carbs are used by your body, you’ll understand why they are so important and why there is a low risk you will get obese by enjoying some carbs now and then.

Let’s be honest, they are tasty as hell as well, and if you restrict yourself from them too much, you’ll eventually binge or develop some sort of eating disorder. I don’t want that for you; you don’t want that for you; your parents don’t want that for you and I am pretty sure the Lord of carbs doesn’t want that for you!

Let’s begin this journey!

Let’s talk about why

Carbs 101

Now, remember how I said whatever carbs you do eat, end up in your blood stream as glucose? I won’t go into much detail about this because it can be quite boring, just remember that carbs (pasta, fruit, veggies, rice, bread, potatoes, grains, beans, etc.) are broken down by enzymes in your upper GI tract and intestines into mainly glucose, then delivered to the liver for processing which then releases glucose into the blood stream.

Why would you want glucose (sugar) in your blood stream?

Because your body works hard to keep around 20 grams of glucose flowing through your blood every hour, on the hour, to provide energy where it is needed throughout your body; most importantly your muscles, liver, nervous system and brain (want an optimal running brain, anyone?).

When your blood glucose level drops below this average 20 grams of glucose, it triggers the release of the hormone, Glucagon, causing your body to become like a glucose vampire, breaking down glycogen (stored glucose compounds in cells) stores in your liver to glucose units and sucking it up into the blood stream.

What’s this process called? For the few science nerds out there, it is called Glycogenolysis. The breaking down of glycogen into glucose units, to be used elsewhere, is done by an enzyme called Glycogen phosphorylase, which is very active during exercise, fasting and low blood glucose levels.

However, when there is too much glucose in your blood stream, the super hero hormone Insulin and the GLUT transporter family (glucose transport proteins) come to the rescue. Now there are a lot of different GLUT transporters, but today I am going to talk about GLUT2 and GLUT4, as these are the main ones that are responsible for the bodies’ transfer of glucose into the muscle, liver and fat cells.

GLUT2 is responsible for pulling in excess glucose from the blood into your liver cells, then using the process called Glycogenesis (which I’ll explain in a little bit) to build glycogen stores within your liver for later use, like if you were exercising, fasting or if your blood sugar levels dropped, like I mentioned above.

The liver can store quite a bit of glycogen as well, about 80 to 100 grams worth before it is full. That’s a decent amount, but your muscles are the powerhouse at storing glycogen. Depending on how much muscle mass you have, it could be anywhere between 300-700 grams of stored glycogen in your muscle cells. When you also factor in that each gram of glycogen pulls in about 3 grams of water into your muscles… You’re going to feel full, pumped and you’ll have the energy to perform like an athlete. Pretty handy!

Let’s get back to Insulin. Insulin is one of the most anabolic hormones to muscle tissue there is. It hits the switch on a cascade of chemical and hormonal messages to tell the muscle cells to bump up their muscle building potential, and having optimal amounts of Glycogen stored in your muscle cells work in tandem to these messages. Since carbs release the most Insulin into the blood stream, compared to protein and fats, it is understandable why carbs are so important in performance and body transformations.

Just think this: Carbs = Anabolic Transformer

Insulin is also important because it helps to transport the excess glucose into your muscle and fat cells by sending a message to GLUT4 to perform the process called facilitated diffusion, which is essentially, transporting glucose to the cells using protein transporters (GLUT4 in this case) which span the cell membrane. GLUT4 is an amazing transporter, mainly because it can be activated by muscle contractions, even without Insulin, which increases facilitated diffusion of glucose into muscle cells, to be stored as glycogen.

Do you know what that means? Your insulin sensitivity and glucose uptake is superior after exercise and your muscles are sucking up all the carbs you eat until they are full. High five for GLUT4!

Now, let me explain the process of Glycogenesis. The enzyme that’s “large and in charge” in this process is called Glycogen synthase. It does the reverse of what Glycogen phosphorylase does: instead of breaking down glycogen into glucose, it builds glucose units up into glycogen. It’s the body’s primary source of stored energy, for fast use, compared to triglycerides’ (storage of fat cells) slow use. Insulin has a large effect on Glycogen synthase, increasing its activity because Insulin and GLUT transfer an abundance of glucose within a cell. If the abundance of glucose within the cell is not going to be used for immediate energy, it doesn’t want to just sit there twiddling its theoretical glucose thumbs, it wants to hang out with its other glucose mates, and Glycogen synthase does exactly that, groups the glucose together as one (Glycogen).

What happens if there is still an excess of glucose in the blood after your liver and muscles cells are full and replenished with glycogen?

This is where it gets interesting, and there are two main possible pathways. It is quite simple really.

Path 1: If you eat more carbs than you need to replenish your glycogen stores, and Insulin and glucose blood levels are still high, your body will transfer to using glucose as your primary energy fuel, instead of fat. This is to burn the excess of glucose off, so to say, to get back to your bodies preferred 20 grams of circulating blood glucose per hour.

Path 2: If your body cannot burn this excess glucose off, causing an obvious caloric excess, which means you ate too many calories for your current need, you start to walk into the situation of storing body fat. Insulin and GLUT4 are primarily responsible for this and that is why Insulin gets such a bad rap in the low carb diet religion. But what isn’t understood is that these fat gains can be quite minimal, if you’re taking part in resistance training and keeping your caloric surplus within sensible limits.

Now this process works almost in the same fashion as storing glycogen: Insulin and GLUT4 transfer the glucose within a fat cell and an enzyme converts it to triglycerides for later energy use. What often doesn’t get mentioned, is that those fat cells will always pull floating fatty acids in your blood stream, before pulling in glucose to build up triglycerides- this is because it actually takes around 10 times the energy (calories) to convert glucose into stored fatty acids (triglycerides), compared to fatty acids building triglycerides.

The long journey that carbs have to take to be stored as fat. AND this is only if your eating more calories than your body needs!

What does all this mean? How can you eat your carbs and minimise fat gain?

I know I could have just left this list of actions that will improve your chances of less fat gain at the start of this article, and I just might in another post… But I would rather inform you on the nitty gritty. So when someone or a blog post tells you that carbs are evil and make you fat, you know they are misinformed and it won’t affect your mindset around enjoying the food you like to eat. Moderation and context is key here guys!

Before I list out easy to understand strategies to minimise fat gain, remember the main element to your diet.

1. Eat more carbs on the days you’re more active, while lowering your fat intake. Let’s say you compete in Crossfit, you’d want to be eating a high amount of carbs during the day, and some fast digesting carbs for immediate energy and to restore your glycogen stores. While lowering your fats you are balancing out your calories and minimising the amount of floating fatty acids to be taking up by your fat cells while Insulin is present.

2. Eat less carbs and more fats on the days you aren’t or less active. If you were sitting on the coach at home on a Sunday, you’d want to make sure the calories you eat that day match your fitness goals. Then eat lower amount of carbs, around the 75-200 gram mark depending on your size and fill the rest with good fats, making sure you get a balance source of Omega 3 & 6 fats. Obviously you have your protein sorted as well.

3. Eat most of your carbs around workouts to take advantage of the increase in muscle and liver glucose uptake, Insulin sensitivity and glycogen resynthesis. This is because of GLUT4’s interaction within the muscle cells after muscle contractions. Also taking advantage of Post Exercise Oxygen Consumption (EPOC), which is present to pay back oxygen debt created when exercising. Increased protein synthesis and turnover is higher as well.

4. Try to eat unprocessed carb sources to take advantage of naturally occurring nutrients and fibre. This increases the amount of energy to digest and absorb the food you do eat, while controlling Insulin spikes. An exception is before, during and after intense or long exercise, mentioned at the top of the list. It will most likely keep you fuller for longer as well.

5. Minimise fructose intake per sitting to below 40 grams. Very high amounts can cause the liver to convert them to fatty acids, once it has taken and used the amount it needs to replenish its own glycogen stores. Just don’t stress about it though.

6. Eat a protein source with every meal you eat, along with fibre and good fats (proportionally needed by following steps 1 and 2). This slows down the release of glucose within your blood stream, which lowers the insulin spike, as it is not needed during a low activity day.

7. Make sure your calorie intake for the day matches your fitness goals. This is the biggest concern here guys! Follow this and you’ll get 80% of the results your most likely looking for!

I hope you enjoyed this as much as I enjoyed writing it for you. I hope you’re not a scaredy cat when it comes to enjoying some carbs now. If you’re serious about your fitness goals and nutrition, then you’re probably going to want to have a look at booking in for a free Fitness Revolution Coaching call with me.

I will help you establish what you really want from your training and nutrition, and then, together, we will find what will drive you to accomplish your goals. After that I’ll set out a game plan for you to use right away, to make your first step towards your goals.

In the meantime, you might also be a good fit for one of my free training programs. You can download it now, from here.

Share and like this post because it will help a lot of people break free from their misunderstanding about carbs.